Au+Au collisions have been studied at center-of-mass energies of sqrt[SNN]=56 and 130 GeV using the PHOBOS detector at RHIC. Charged particle multiplicities have been measured as a function of center-of-mass energy, centrality and pseudo-rapidity, η. A total of 4100 ± 400 charged particles are observed in the pseudo-rapidity range -5.4 < η < 5.4 for the most central collisions. A strong elliptic flow signal is seen in peripheral collisions at η = 0. The measurement of an antiprotons to protons ratio of p̄/p = 0.60 ± 0.04(stat) ± 0.06(syst) indicates that a nearly baryon-free region is created at midrapidity.